From: ssmoot@...
Date: 2006-01-07T10:43:02+09:00
Subject: Re: Using ri inside irb -- error in Pickaxe?

"*names.map" should be "names.map". The * before a variable name in a
method definition is basically equiv to the "params" keyword in
Microsoft languages if that helps.

%{} is basically short-form for a HEREDOC. I don't like it personally.
A slightly cleaner example (that works) might look like this:

def ri(*names)
  system("ri #{names.map { |name| name.to_s }.join(' ')}")
end